There are many industrial water systems, including, but not limited to, cooling water systems and boiler water systems. Because water resources are becoming limited and efficient utilization of water is required, various methods have been adopted to reduce the amount of water used.
As the methods for reducing the amount of water are put into practice, unfavorable events occur, such as the occurrence of corrosion and the formation of scale, because the quality of the water in the system is progressively deteriorated.
To prevent or minimize these troubles, various kinds of treatment agents for treatment of water systems have been used. It has been found that organic substances, including certain types of treatment polymers, are effective for preventing formation of scale and suppressing the occurrence of corrosion. These certain types of treatment polymers are known to persons of ordinary skill in the art of industrial water treatment and are widely used by themselves or as one of many possible components in scale and corrosion inhibition products. Such treatment polymers generally exhibit activity against scale and corrosion when added to water in an amount in the range of from about 1 to about 100 milligrams of solid component active per liter of water.
When a treatment polymer is used for preventing formation of scale and suppressing the occurrence of corrosion, the concentration of the treatment polymer in the water system is the important factor to perform the desired function with good efficiency. For example, a treatment polymer added to a cooling water system can be consumed by many causes. With consumption, the amount of the treatment polymer dissolved in the cooling water does not remain the same as the amount added to the cooling water. Therefore, it is important for the optimum operation of an industrial water system that practical methods are known to determine the concentration of treatment polymers in the water of the industrial water system.
In general practice, the amount of the treatment polymer added to the water in an industrial water system can be measured using various analytical methods. The use of an inert fluorescent tracer or mass balance measurement method as described in U.S. Pat. Nos. 4,783,314; 4,992,380; and 5,171,450, hereby incorporated by reference, to perform this analysis, is known in the art.
In the inert fluorescent tracer method, an inert fluorescent tracer is added to an industrial water system, with the amount of inert fluorescent tracer added being proportional to the amount of the treatment polymer added. By using a fluorometer to measure the fluorescent signal of the inert fluorescent tracer, the amount of the inert fluorescent tracer can be determined by using a calibration curve to relate the amount of fluorescent signal detected to the amount of the inert fluorescent tracer present. Because the inert fluorescent tracer and the treatment polymer are added to the industrial water system in known proportions, by knowing the amount of inert fluorescent tracer present it also means that the amount of treatment polymer present is known.
The inert fluorescent tracer method can be conducted on-line in real time so that any changes in the amount of treatment polymer being added to the system can be made immediately.
As a complement to the use of an inert tracer system, it has been found that treatment polymers to be used as components of scale and corrosion inhibitors in industrial water systems could be monitored if tagged with a fluorescent monomer. The amount of fluorescent monomer incorporated into the polymer must be enough so that the fluorescence of the polymer can now be adequately measured, however, it must not be so much that the performance of the polymer as a treatment agent for the water is decreased. Because the concentration of the tagged treatment polymer itself can be determined using a fluorometer, it is now possible to measure consumption of the treatment polymer directly. It is important to be able to measure consumption directly because consumption of a treatment polymer usually indicates that a non-desired event, such as scaling, is occurring. Thus by being able to measure consumption of the polymeric additive, there can be achieved an on-line, real time in situ measurement of scaling activity in the cooling system.
Certain tagged polymers are known, see U.S. Pat. No. 5,986,030, hereby incorporated by reference. However, there is not an abundance of viable tagged polymers for use in industrial water systems. Therefore, it is desirable to provide additional tagged polymers that have a fluorescent signal so that you can use a fluorometer to measure the fluorescent signal of the tagged treatment polymer and determine the concentration of tagged treatment polymer currently present in the industrial water system from that information.
It is known that tagging of polymers is difficult to accomplish because of the difficulty in chemically combining fluorescent moieties with non-fluorescent polymers. In order to synthesize tagged treatment polymers it is also desirable to provide fluorescent monomers that are readily polymerized to form tagged treatment polymers.
The aspects, objects and the several advantages of this invention will be apparent from the following specification and appended claims.